Eductors are pieces of equipment that are used to continuously mix and/or combine two or more fluids within a fluid mixing chamber defined by an eductor's housing. After mixing within the fluid mixing chamber, the eductor then discharges the mixed fluid through one or more fluid outlets, which are in fluid communication with the fluid mixing chamber. Oftentimes the eductors manage two or more different fluids, such as different air streams, for example an entrained air stream and a motive air stream, without solid additives contained in either air stream. Examples of such eductors include eductors that are utilized with jet engines to cool the exhaust. However, some eductors do manage at least one fluid that contains solid additives, for example pulp fibers, that mixes with another fluid, such as air only.
One problem of known eductors is that the mixed fluid within the fluid mixing chamber of the eductors and the mixed fluid exiting the eductors' fluid outlet is spatially non-controllable, especially when the entrained fluid comprises a plurality of solid additives, such as fibers, for example pulp fibers. In other words, the distribution of solid additives, especially in the cross-machine direction, present in the entrained fluid cannot be controlled in known eductors, which results in a random distribution of the solid additives within the fluid mixing chamber and in the mixed fluid exiting the eductor's fluid outlet.
It is believed that this non-controllability of the mixed fluid within the eductors' fluid mixing chamber and thus the mixed fluid exiting the eductors' fluid outlet is caused by the lack of ability of the eductors to be CD controllable, for example to provide a variable motive fluid into their respective fluid mixing chambers to create less non-uniformity and/or more uniformity and/or uniformity in the mixed fluid's CD profile, especially if the mixed fluid comprises a plurality of solid additives, such as fibers, for example pulp fibers.
As shown in Prior Art FIGS. 1A-1C, an example of a known non-spatially controllable, for example non-CD controllable, eductor 10 having a housing 12 that lacks the ability to create and provide a variable motive fluid to its fluid mixing chamber 14. As shown in FIGS. 1A-1C, the eductor 10 comprises a housing 12 that defines a fluid mixing chamber 14, an entrained fluid inlet 16, an invariable motive fluid inlet 18 (for example a non segmented, not two or more discrete, separated zones as clearly shown in FIG. 1C), such that the motive fluid entering the fluid mixing chamber 14 from the invariable motive fluid inlet 18 would not create a variable motive fluid (for example would not have two or more zones that differ in properties, such as pressure, velocity, mass, and/or flow), and a fluid outlet 20, for example a mixed fluid outlet. The entrained fluid inlet 16, invariable motive fluid inlet 18, fluid outlet 20, and the fluid mixing chamber 14 are in fluid communication with each other during operation of the eductor 10, but the eductor offers no way to spatially control the mixed fluid, for example control the CD profile of the mixed fluid, especially if the mixed fluid contains a plurality of solid additives.
Further, most of such known non-spatially controllable eductors have a circular cross-section fluid mixing chamber, like the one shown in FIGS. 1A-1C, and are incapable of creating and/or providing a variable motive fluid during operation of the eductors and thus lack the ability to manipulate the mixed fluids within the eductors with respect to the mixed fluids' CD profiles, such as pressure, velocity, mass and/or flow CD profiles.
Prior Art FIGS. 2A-2C illustrate an example of another known eductor 10 comprising a housing 12 that exhibits a non-circular cross-section (a polygonal, such as rectangular, or elliptical cross-section) fluid mixing chamber 14. This eductor 10 manipulates an induced gas, for example air stream (entrained air stream) represented by arrows A entering the eductor 10 through its entrained fluid inlet 16 by placing steering vanes 22 within the fluid mixing chamber 14 to selectively guide the induced air stream A to direct pulp fibers 24 within its motive fluid, its invariable motive fluid stream represented by arrows B entering the eductor 10 through its invariable motive fluid inlet 18 (for example a non-segmented, not discrete, separated zones as clearly shown in FIG. 2C, which has a portion of the housing 12 broken away) such that the motive fluid entering the fluid mixing chamber 14 from the invariable motive fluid inlet 18 would not create a variable motive fluid (for example would not have two or more zones that differ in properties, such as pressure, velocity, mass, and/or flow), toward selected areas of a collection device, such as a belt (not shown). It too, like its circular cross-section cousins, is incapable of creating and providing a variable motive fluid during operation of the eductor 10, thereby relying on changes in the baffle positions on the entrained fluid side of the eductor to effect the velocity profile in the CD direction. The presence of these baffles prevents the introduction of particles into this stream and limits the applications to which this technology can be applied.
Another known eductor is shown in U.S. Pat. No. 4,400,138 that shows an eductor with multiple, adjustable motive air inlets. The cross section of this eductor, however, is circular, with an CD/MD ratio of 1.0. Since these adjustable motive air nozzles are evenly spaced around the eductor discharge, there is no ability of this device to adjust flow in the cross direction, and thus is a non-spatially controllable, non-CD controllable eductor.
Still another known eductor is shown in U.S. Pat. No. 7,014,441 that illustrates a planar eductor with a high aspect ratio (CD/MD) with adjustable motive air nozzles. As can be seen from its figures, this eductor is not, however, controllable and/or adjustable in the CD, but only in the machine direction.
Additional descriptions of known eductors and their properties and operation are described in the following references: Blevins, Robert D, “Applied Fluid Dynamics Handbook”, section 9.5, ISBN 1-57524-182-x; Young, Munson, and Okiishi, “A Brief Introduction to Fluid Mechanics” ISBN 0-471-13771-5; Silvester, R. and N. H. G. Mueller, “Design Data for the Liquid-Liquid Jet Pump”, J. Hydraulics Res. 6, 129-168 (1968); and Mueller, N. H. G., “Water Jet Pump,” ASCE J. Hydraulics Div. 90, 83-113 (1964).
In light of the foregoing, there is a need for a spatially controllable, for example CD controllable eductor, especially an eductor that manages the flow of solid additives, for example pulp fibers, that is capable of creating and/or providing a variable motive fluid, and more particularly controlling and/or adjusting the CD profile of the mixed fluid within the eductor in order to influence the mixed fluid of the eductor and result in a never-before achievable result in the exiting mixed fluid and/or ultimately a product made from the exiting mixed fluid. Further, there is a need for an eductor that is a CD controllable eductor that is capable of being manipulated during operation of the eductor to control and/or adjust the pressure, velocity, mass and/or flow CD profiles of the mixed fluid within the eductor, for example within the eductor's fluid mixing chamber, and processes using such an eductor.